In the field of magnetic storage systems, when reading data from tracks written on magnetic media, such as the media employed in hard disk drives, tape drives, etc., distinct channels are used which form pathways from the sensing element to the unit responsible for processing the read-back signals. However, at high storage a real densities, conventional methods and devices which process the read-back signals from the magnetic media become highly sensitive to undesired signal variations, such as those caused by noise or parasitic events, and consequently are not able to recover the stored digital information in a reliable way. Noise may be caused by the electronics components used to condition the signal generated by the magnetic read head, by coupling events during the transmission of signals on connector cables, as well as by other phenomena that affect the way data are effectively written on and read back from the storage medium (such as data dependent media noise).
To address these issues, attempts have been made at improving the performance of data detection in read channels for magnetic storage systems, in particular tape storage systems. Known solutions to improve the performance of data detection in read channels that go beyond a traditional partial response maximum likelihood (PRML) channel design include noise-predictive maximum likelihood (NPML) schemes for signals disturbed by stationary or nonstationary noise, post-processing techniques, and other methods. As the noise process in a recording channel tends to have an autocorrelation characteristic that extends over a large number of symbol durations, which typically happens with a noise process having a strong moving average component, long finite-impulse response (FIR) prediction filters must be used to achieve efficient noise whitening. This represents a serious drawback in view of the high speed implementations typically needed in read channels, as well as in terms of the required chip area.
Therefore, a better method of improving the performance of data detection in read channels for magnetic storage systems would be very beneficial.